Optical study of a new phase LaGa3O6:RE3+ (RE=Pr, Nd, Eu) in the La2O3-Ga2O3 system

The absorption and emission spectroscopies of RE3+ ions embedded in a new phase, LaGa3O6, owing to the La2O3-Ga2O3 binary system (RE = Pr, Nd, Eu) are discussed. The L-2S+1(J) level degeneracies are completely lifted in accordance with the low point symmetry of the site occupied by the rare earth ion in LaGa3O6. The energy level schemes deduced from the data are reproduced by considering a crystal field (CF) effective Hamiltonian involving the nine real and five imaginary parameters required for the C-2 or C-s symmetry of the rare earth site. The rms deviation is satisfactory for the three simulations. However, the strong variation of the CF parameters between Pr3+ and Eu3+ in LaGa3O6 suggests the possible limit of existence of the phase, intimately correlated to small variations of the rare earth ionic radius.